A vane-cell pump having the features mentioned has already been disclosed in DE 41 10 734 A1. In this pump, the rotor has a bore system consisting of a number of interconnected radial and axial bores attached to the working chambers. The axial bores of said bore system are covered by an outlet valve designed as a check disc. The check disc, coordinated with all of the working chambers, prevents previously pressurized oil from flowing back into the partly filled working chambers. It is possible, in this manner, to prevent damage caused by cavitation. The already known vane-cell pump works with the advantage of so-called suction control, that is, the pump sucks only the amount of oil needed at the time. Accordingly, an excessive amount of oil is not pressurized which is subsequently sent back to the suction zone via a flow-control valve. Input can be saved in this manner. The check disc, closing the axial bores in the rotor, is compressed by a pressure element supported in one front plate, generating undesired friction between the rotor and the check disc. Because of the radial and axial bores passing into each other at right angles, the pump has, in addition, relatively high inner drag.
The problem on which the invention is based is to find a suction-controlled vane-cell pump as free of erosion as possible and having low inner drag and smooth operation. Another requirement is to accommodate the parts required for suction control of the pump in a narrow space so that the body of the pump can be built small and yet capable of reaching a high reliability of operation.